Brain Tumor Grading

Brain Tumor Grading

A neuropathologist, in collaboration with your neuro-oncologist and neurosurgeon, will examine your biopsy sample to determine the exact type of brain tumor you have, whether the tumor is benign or malignant and how serious it is (its grade).

Staging is the term oncologists use to define where cancer is located and how much it has spread. A staging system is used for most other types of cancer, but for tumors of the brain grading is often of greater importance. This is because most primary brain tumors do not spread beyond the central nervous system.

Northwestern Medicine uses a grading system developed by the World Health Organization. This helps them determine how to best treat brain tumors. Grading refers to how abnormal brain tumor cells look compared to healthy cells. The grade also gives your physician an idea of how the tumor may behave. Results obtained from looking at a brain tumor tissue sample from a molecular level can provide even more information about the tumor, including how aggressive the tumor may be.

Primary Tumor Grade Grade Description
Grade 1*
  • Benign
  • Slow-growing cells
  • Look almost normal
  • Least aggressive
Grade 2
  • Relatively slow-growing cells
  • Look slightly abnormal
  • Invade normal tissue
Grade 3
  • Malignant
  • Actively growing cells
  • Look abnormal
  • Invade normal tissue
Grade 4
  • Most malignant
  • Quickly reproducing abnormal cells
  • Look very abnormal
  • Necrosis (area of dead cells) in the center of the tumor

*Normally treated with surgery alone.

Related Resources

Lou and Jean Malnati Brain Tumor Institute at the Robert H. Lurie Comprehensive Cancer Center at Northwestern Memorial Hospital
Brain and Spine Tumor Center brochure: Learn about the Brain and Spine Tumor Center at Central DuPage Hospital and Delnor Hospital